fix(beszel): review fixes for MCP and widget styling

- Throw TRPCError instead of returning null when no integration
- Sort beszelRouter import alphabetically in mcp.ts
- Replace ternary with lookup table for background color
- Mention integration_all in MCP server instructions

apps/nextjs/src/app/api/mcp/[transport]/route.ts

@@ -148,7 +148,7 @@ If \`hasUseAccess\` is false, the API key owner lacks permission for that integr
 
 **"Check server health"** → Use \`healthMonitoring_getSystemHealthStatus\` for NAS/server metrics or \`healthMonitoring_getClusterHealthStatus\` for Proxmox clusters.
 
-**"Check Beszel systems"** → Use \`beszel_getSystems\` to list all monitored systems with CPU/memory/disk/network status. Use \`beszel_getAlerts\` for active alerts and history. Use \`beszel_getSystemStats\` for historical metrics of a specific system (requires systemId from \`beszel_getSystems\`).
+**"Check Beszel systems"** → Call \`integration_all\` to get Beszel integrationIds, then use \`beszel_getSystems\` to list all monitored systems with CPU/memory/disk/network status. Use \`beszel_getAlerts\` for active alerts and history. Use \`beszel_getSystemStats\` for historical metrics of a specific system (requires systemId from \`beszel_getSystems\`).
 
 **"Manage Docker containers"** → Use \`docker_getContainers\` to list containers with status/CPU/memory, then \`docker_startAll\`/\`docker_stopAll\`/\`docker_restartAll\` with container IDs.
 

packages/api/src/mcp.ts

@@ -9,6 +9,7 @@ import { iconsRouter } from "./router/icons";
 import { infoRouter } from "./router/info";
 import { integrationRouter } from "./router/integration/integration-router";
 import { inviteRouter } from "./router/invite";
+import { beszelRouter } from "./router/widgets/beszel";
 import { calendarRouter } from "./router/widgets/calendar";
 import { dnsHoleRouter } from "./router/widgets/dns-hole";
 import { downloadsRouter } from "./router/widgets/downloads";
@@ -16,7 +17,6 @@ import { healthMonitoringRouter } from "./router/widgets/health-monitoring";
 import { mediaRequestsRouter } from "./router/widgets/media-requests";
 import { mediaServerRouter } from "./router/widgets/media-server";
 import { smartHomeRouter } from "./router/widgets/smart-home";
-import { beszelRouter } from "./router/widgets/beszel";
 
 export const mcpRouter = createTRPCRouter({
   app: appRouterForApps,

packages/api/src/router/widgets/beszel.ts

@@ -1,3 +1,4 @@
+import { TRPCError } from "@trpc/server";
 import { observable } from "@trpc/server/observable";
 import { z } from "zod/v4";
 
@@ -160,7 +161,9 @@ export const beszelRouter = createTRPCRouter({
     )
     .query(async ({ ctx, input }) => {
       const integration = ctx.integrations[0];
-      if (!integration) return null;
+      if (!integration) {
+        throw new TRPCError({ code: "BAD_REQUEST", message: "At least one Beszel integrationId is required" });
+      }
       const innerHandler = beszelStatsRequestHandler.handler(integration, {
         systemId: input.systemId,
         timePeriod: input.timePeriod,

packages/widgets/src/beszel-system-grid/component.tsx

@@ -356,7 +356,8 @@ export default function BeszelSystemGridWidget({
   const board = useRequiredBoard();
   const colorScheme = useComputedColorScheme("light");
   const opacity = board.opacity / 100;
-  const backgroundColor = colorScheme === "dark" ? `rgba(57, 57, 57, ${opacity})` : `rgba(246, 247, 248, ${opacity})`;
+  const bgBase: Record<string, string> = { dark: "57, 57, 57", light: "246, 247, 248" };
+  const backgroundColor = `rgba(${bgBase[colorScheme]}, ${opacity})`;
 
   const { data: results = [] } = clientApi.widget.beszel.getSystems.useQuery(
     { integrationIds },